User guide

22
Release Notes for Cisco IOS Release 12.4T
OL-8012-09 Rev. B0
Platform-Specific Information
PPP over AAL5SNAP Encapsulation Support
PPP over AAL5SNAP encapsulation is not supported, although the context-sensitive help mentions that
it can be configured.
Cisco 800 Series Router Clock—CSCdp09409
To run IP Security (IPSec) successfully, the Cisco 800 series router clock needs to be set accurately.
Cisco 800 series router clocks are set and maintained using Simple Network Time Protocol (SNTP). For
best results, set up a Network Time Protocol (NTP) server to periodically send time information
messages to Cisco 800 series routers. See the SNTP configuration and command reference
documentation for configuration instructions. If you do not have an NTP server, you must reset the
Cisco 800 series router clock using the clock set command each time you restart the router.
Dial Peer Limitation
The isdn answer1 and isdn answer2 commands determine which called telephone numbers, for
example, 555-0100 and 555-0199, a Cisco 800 series router can answer. Using these commands limits a
router to using the two dial peers that contain the telephone numbers 555-0100 and 555-0199. (When
not using these commands, a router can use up to six dial peers.)
Excessive ISDN Line Activation
The following protocols send updates that can cause an ISDN line to be activated excessively, thereby
increasing your monthly ISDN line cost:
• IP
• User Datagram Protocol (UDP)
• Internetwork Packet Exchange (IPX)
• Cisco Discovery Protocol (CDP)
• Simple Network Time Protocol (SNTP)
For information on preventing this situation, refer to the Cisco 800 Series Routers Software
Configuration Guide. This guide contains information on setting up extended access lists to prevent IP,
UDP, IPX, and SNTP updates from activating the ISDN line. For CDP, ensure that you enter the no cdp
enable command to disable CDP.
Hanging During Boot
If an illegal console configuration is issued to the router, the console will fail the power-on self-test
(POST) test during boot and cause the router to pause indefinitely. There is no way to recover a unit in
this state except by pulling the soldered boot Flash and reburning the boot ROM.
This problem has been resolved in TinyROM version 1.0(3), a downloadable ROM upgrade available
from Cisco.com. Please contact Cisco to upgrade to this version or a later version, and prevent this
problem from occurring.
Phone Mate Answering Machine Model 9200
A Phone Mate answering machine model 9200 failed to recognize the ringing signal sent by AMD R79
ringing Subscriber Line Interface Card (SLIC). This failure was confirmed by testing against Phone
Mate model 3750 and the newer model 9300.